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A bit about motors, magnets, AC and DC, and weird little widgets called IGBTs, all the while trying to answer some more of your questions. (And yes, we are opening a Detroit office, but that’s another story.)

Nikola Tesla was a strong believer in AC (alternating current) as a means of distributing electricity because it was more efficient than DC (direct current, as favored by Thomas Edison), and because it was easy to step an AC voltage up or down using a transformer made of nothing more than a stack of steel sheets and some coiled-up wire. Plenty has been written on this subject. I recommend the following books.

Rewind all the way to 1888: Nikola Tesla invented the polyphase AC induction motor (US Patent numbers 381968, 381969, 382279, 433700, 433701, and 555190). Tesla was interested in such a motor because it was simpler, and because it could be driven directly from AC transmission lines or from a dynamo without need for rectification. Tesla worked to perfect the AC induction motor, and most of the motors we use in plug-in appliances and equipment are directly derived from his work.

AC Induction motors have several advantages over DC motors: they have no field windings or permanent magnets of any sort; they have no brushes or commutators to wear out; they can be highly efficient. Tesla himself recognized that AC induction motors could work well in cars. However, they were never used in production cars in his time because it was nearly impossible to convert DC from batteries into AC to drive the motor. (The vacuum tube was still pretty neat stuff –silicon was most useful as a beach topping, no decent diodes, no transistors, etc.)

So AC induction motors found their way into industry and into appliances, using AC as generated by dynamos. For the last 100 years they were mostly designed and optimized to work at a fixed frequency: 60 Hertz here in the USA, the frequency of the alternating current in every electrical outlet in our homes. (This frequency -- still used today -- was chosen over a hundred years ago by Tesla.)

(For the less technical, what does AC mean? AC means that the current changes direction smoothly back and forth like waves on the beach – flowing in, then back out. If you could listen to 60 Hertz, it would sound like a low, smooth tone. Higher frequency means higher pitch; those annoying beeps from microwaves and other electronic goodies are around 2,000 Hertz. Your hearing probably tops out around 20,000 Hertz.)

Electric cars used simple-to-control DC motors all the way into the 1990’s, See a long list here.

DC motors don’t need much to make them turn – hook ‘em up to a battery, and they go. Maybe you played with a dc motor yourself in school, in a slot car, whatever. If you take one apart, you will find the same thing whether it is big or small, old or new: a rotor (the part that spins), made up of a bunch of wire wrapped around a frame on a shaft, and a casing that has a couple of magnets attached to it. The wires to the motor attach to “brushes” that ride on a dohicky on the rotor’s shaft, called a commutator. The brushes and the commutator conspire to run current through the coiled wire of the rotor (creating magnetism), and flipping the direction of the current (and therefore the magnetism) back and forth as the rotor spins. There has been plenty of optimization over the years – fancy “rare earth” magnets, better commutators, even tricky elimination of the brushes in (cleverly named) brushless DC motors.

JB warns me:

“Be a bit careful here. The brushless DC motor is actually an AC motor. You need an inverter to drive it! A better name for this type of motor would be: “synchronous permanent-magnet AC motor.” Most people ask why we don’t use a brushless DC permanent magnet motor, like all hybrids today use. We chose not to use one of these mainly because of the wide efficiency plateau that we get from an AC induction motor (which means high efficiency over a wide RPM and power range), not because it is really a DC motor.” (Some of you have asked about the use of niobium or other advanced magnets in our car. If we used a brushless DC motor, we’d have such magnets. But we don’t :-) ) Even today, practically all hobbyists who are making their own electric car use DC motors because control is so easy.

But Nikola Tesla was right: an AC induction motor is inherently more efficient, lighter, simpler, and more reliable than a DC motor – and would make a better electric car if only it were feasible to convert the battery’s DC into AC easily.

Fast forward to 1986. Transistor technology has come along and been refined enough that it is possible to create high-power AC from DC without a lot of wasted energy. Aerovironment was developing the Sunraycer, a solar-powered racer for GM. Al Cocconi (the “A.C.” of AC Propulsion), was working for Aerovironment, at the time. There, he figured out how to gang a whole lot of MOSFETs (fancy transistors) together to make an “inverter” for the Sunraycer so they could use a light weight AC induction motor.

But this was not your ordinary inverter. If you bought an inverter for your car or RV to power household appliances, that inverter would simply make good old 60-Hertz like what you get from your wall outlets. In contrast, Cocconi’s inverter created a variable-frequency AC waveform for the motor. (In the same era, several others created similar variable-frequency inverters for EVs and other applications – decent power transistors changed everything.)

Why variable frequency? A little digression into how an AC motor works:

The AC electricity driving the motor powers the stator (the stationary windings around the spinning rotor) and creates a rotating magnetic field. Tesla’s original motors used 3 “phases” of AC to drive the motor: 3 wires to the motor, each with the same frequency AC, but at a different phase. (Sorry – I can’t think of an easy way to explain this!) Lower-power motors today use a single phase, which (annoyingly) use two wires.

Motor engineers coined a concept called “slip,” which is the difference in rotational speed between this rotating field and the rotational speed of the rotor. The torque of the motor is proportional to the slip. So – if you want a certain amount of torque from an AC motor, you measure the speed of its rotor, and adjust the AC frequency to cause the magnetic field to rotate the right amount faster than the rotor (or slower for regen braking).

An AC induction motor is sometimes called a “squirrel cage motor” because the working part of the rotor looks like one of those cages that pet rodents run around in – a shaft with two metal rings connected together by a bunch of metal bars. (Note: there are generally no wire windings in the rotor of an AC induction motor.) Early on, Tesla figured out that he could fill up the squirrel cage (where the squirrels might run) with a stack of steel laminations to increase the power of the motor.

Tesla mostly used copper to make his squirrel cages, but had a difficult time fabricating them. For this reason, Tesla came to advocate aluminum for the rotor instead of copper, even though this reduced the motor’s efficiency considerably.

As noted above, AC motors designed for appliances usually run at one speed. Some of you have commented that we should use a Continuously Variable Transmission (CVT) to match our motor speed to the desired speed of the car. This would be true if we ran our motor on a fixed frequency.

But we don’t. Like the GM cars, and like other AC electric car motors, we feed the motor with a variable frequency AC waveform, using frequency to regulate torque and therefore speed.

Skip to 1988: The team at Aeroviroment got the GM contract to create the Impact (the precursor to the GM EV-1), so they designed a custom AC induction motor to go with Cocconi’s MOSFET-based variable frequency inverter.

The folks at Hughes/GM didn’t like the large number of MOSFETs that Cocconi used, and proposed instead to use the new-fangled IGBT transistors like those from International Rectifier. You can read about all this in the book The Car That Could. The Hughes/GM engineers liked these better because they were easier to control and many fewer transistors were needed. According to legend, Cocconi was at first resistant to using IGBTs rather than the MOSFETS he already understood. True or not, the EV-1 used IGBTs.

Fast forward again to 1992: Al Cocconi started AC Propulsion to make EV motors and matching inverters. AC Propulsion developed their Power Electronics Unit (PEU) using IGBTs similar to what Cocconi learned about from the guys at Hughes/GM.

Fast forward once more to 2003: Tesla Motors’s Power Electronics Module (PEM), in turn, uses a similar kind of variable frequency, IGBT inverter, based on what we learned from our friends Al Cocconi and the rest of the team at AC Propulsion, as well as from what JB and I had learned in our own careers as electrical engineers. Over the last 3 years, this PEM has been refined and improved by Tesla’s team of electrical, firmware, and manufacturing engineers.

At the same time, Tesla’s motor engineering team developed our own custom 3-phase AC induction motor – based on Tesla’s patents, based on the EV-1 motor, based on the AC Propulsion motor. Like Tesla’s motors, the EV-1 motor, and the AC Propulsion motor, ours gets its incredible efficiency largely due to its copper rotor.

We’ve studied the EV-1 motor carefully. The technique they used to construct their copper rotor was not great, resulting in suboptimal efficiency, and (I suspect) low manufacturing yield.

We have studied AC Propulsion’s rotor manufacturing technique. Their process creates a motor with much better efficiency. But there is quite a bit of hand labor and tweekmanship in the process, and it would not work for the production volumes we forecast at Tesla.

We studied other companies who cast copper rotors like Favi. But their process yielded rotors with lower efficiency than AC Propulsion’s.

So we set out to create our own copper rotor fabrication process. It took us a few years, but it worked: our rotors are readily mass produced in our own factory in Taiwan, and their performance is quite nice. (How we do it is a secret. I don’t keep a lot of things secret from you, but this is some of our secret sauce! That’s why we didn’t outsource the construction of this piece.)

Here’s the cool thing: if you handed one of our motors to Nikola Tesla, he’d recognize it immediately as his own invention. Nice job of optimization, but clearly his.

I think a good way to describe three signals that are the same, but out of phase is as follows...Think of three people who are going to sing "Row Row Row your Boat" in a "Round Robin" style....One starts singing "Row Row Row your boat" and as he starts to say "gently down the stream" the second person starts singing "Row Row Row your boat"
and as the second guy says "gently down the stream" the third guy starts singing "Row Row Row your boat." Now you have 3 people singing the same exact song at slightly different starting points....thats what you have with 3-phase AC, three identical signals (or songs, to use my example) with three different "starting points" ( different phases. )

Hope that helps someone...

-Jim

David

1:07pm | 10月 18, 2006

You could think of a 3-phase motor as three people pushing a merry-go-round by tugging on posts around the edge. As each post goes by each person, they grab the post and pull on (torque) it until it is too far away to hold on (slip). Of course, the people would have to be on a rotating ring on the outside of the merry-go-round for this to be close to what is happening.

Considering how many posters here don't understand the second law of thermodynamics, it's probably hopeless to explain 3 phase power.

I am curious as to if you are a publicly traded if so what is it under. I am interested in getting in on the bottom floor of this company. I know I dont have any qualifications I could be used for as far as mechanical or electrical but I do feel you are the future for America and it dependence on oil as the life blood for the US. I am really impressed with the car and can't wait to see your sedan model and eventual models. My wife is saying it just doesn't seem cost effective for us to purchase one of these vehicles I tell her there is no way it is not effecient for us to purchase one. On average we pay $5000 a year (low end numbers) on gas alone. As I am not sure how much the batteriers are to replace I am sure it is probably the cost of one years worth of gas. I told her I am sure when you mass produce the next model it will be considerably less than the Tesla Roadster. Well I am going to shut up now. Thanks for getting me excited about automobiles again.

Sorry for the tangent...but just saw the Roadster on the cover of Robb Report...if this your first major magazine cover, congrats! If not, congrats anyway!

Dave

1:54pm | 10月 18, 2006

Martin, Please bring Tesla Motors to the North American International Auto show in Detroit in January. I believe this would be a terrific opportunity to showcase the Tesla Roadster and give it the attention it deserves.

I see that others have analogized the multi-phase approach. I was going to offer the simple phrase "staggered timing," which is a concept that is familiar to people who understand ICE engines. Those engines operate in timing-critical "phases," too. But the analogies to a musical round and a merry-go-round certainly make clear why and how "staggered timing" is useful. I appreciate David's and Mr. Gawron's succinct descriptions, not to mention Martin's essay on how AC and DC motors work, and the history lesson.

Speaking of history lessons, I would like to encourage Tesla to work with the History Channel. NBC's Today show was recently quite helpful in producing and broadcasting what was, essentially, a video love letter to and infomercial for the Roadster. The History Channel series, "Modern Marvels," would seem to provide a perfect showcase for a look at the Roadster's historical precursors -- technological, political, and economic -- all combined and converged in our era to yield the Roadster and other similarly-pedigreed EVs. An hour's in-depth, professionally produced look at the Roadster and how it came to be could only raise awareness of the state of the EV, and stoke the demand for the Roadster and follow-on vehicles.

Joshua Mize

3:11pm | 10月 18, 2006

Another excellent blog....I especially liked the part where you said hand making the copper rotot like AC propulsion does wasnt an option because you expect your volume to be too high for that. Thats exactly what I want to hear. I am very anxious to see some volume and can't wait for the sedan model to break the auto market wide open. You guys are doing an awesome job, please keep it up. One question....all of us desperately waiting for the sedan....will we have to wait for the sedan, the model we can actually purchase, to become available to get a test drive? Or, when the showroom in our area opens up, will they let us go ahead and test drive the Roadster? I'd be interested to know, because if so I'd definitely be making a road trip to Miami in 2007 to take a test drive. It would be totally worth the trip. Thanks again for the update.

toutlemonde

3:51pm | 10月 18, 2006

Europe sell the car in europe, you cant loose petrol costs twice as much in europe than in the US, you couls sell 100 cars in London alone

RDE

5:50pm | 10月 18, 2006

Want to set middle america back on it's ear? Buy a left-over Nascar stock car, put a Tesla drive train in the front and a second in the rear. Crank in lots of aerodynamic down force, rent the Datona speedway for a couple of days, invite tons of press, and run some laps 20 mph faster than the Detroit Iron good ol boys!

ps. either stop printing so much must-read material on this site or fire your webmaster and hire someone to replace this eyestrain black hole with a readable format.

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Editor's Reply: The Editor thanks you for your feedback.

Stephen Salley

8:01pm | 10月 18, 2006

umplug the roadster with onboard hydrogen production.

Jim Wells

8:50pm | 10月 18, 2006

Always been a big fan of Tesla's work and loved to "play" with Tesla coils as a kid, lighting up floresent lights from a couple feet away.....or creating deafening explosions zapping a bowl of hydrogen bubbles...

A "cool" homage to Tesla would be a rear spoiler with 100K coil and conductor at the other end---so at night--or when a car theif got near---the coil could blast "Tesla Fire" out.

Thanks again, Martin (& JB) for continuing to put effort into the blog. I can see you are proud of what you are doing and still have a real "spark" of enthusiasm left even though I imagine your life is so overwhelming now with all the work required to coordinate such an effort with such a small staff.

So, you guys have been doing a great job of paying homage to those who laid the groundwork for your product(s), particularly Mr. Telsa himself, and you have been good about keeping us informed about what you are doing today, so perhaps in the next blog you could talk more about your plans for the future. I know you need to keep some of that secret, and you don't want to mis-set expectations of things you can't be sure to deliver, but maybe you can talk in some generalities.

Do you dream of doing more than cars someday? Electric boats or planes?

What would your "dream Tesla auto" of 2020 look like? Do you foresee 1000 mile range by then from your technology crystal ball? Will everything be all wheel drive? Will Tesla be selling worldwide? Along with the excitement of Nanotech UltraCaps, and thin film solar cells, are you tracking some other upcoming technology you hope will pave the way for some more breakthroughs? Do you see any superconductive parts helping?

Global warming & dependence on oil are certainly good things to reduce through more proliferation of EVs, but there are also other problems you could someday try to tackle. Overcrowded highways is one. Do you have dreams about that? Cars that drive themselves? Cars that lock onto cars in front with radar cruise control? GPS & auto-blogs to programmatically create carpool opportunities? I am just throwing out random ideas in the hope that you might be willing to share some of your views of the distant future for this industry in general, if not just specifically for your team.

With many companies lucky if they have a good 18 month roadmap, I could assume that you are too busy with the "here and now", but I get the feeling that you and your team has no shortage of dreamers thinking about future opportunities down the road.

Michael

4:17am | 10月 19, 2006

I'm surprised that there was no reference to what compromises would be required to utilize the friesen motor. I'm remembering a challenge offered by the CEO when he stated that he bet he could best your motor efficiency by 40% at low speed and 15% at highway speeds.

Just seems like there must be some reason why an existing motor was not useable and you had to develop your own at much expense and loss of time.

Al Levesque

4:17am | 10月 19, 2006

Great historical discussion!
Please, please, change the page background color so that reading this great information will be a pleasure instead of torture!

Joshua Mize

4:46am | 10月 19, 2006

I like the black background. I think if we took a vote, the black background would win....ignore the naysayers...keep up the good work webmaster.

Michael Lawson

7:51am | 10月 19, 2006

Wow, what an awesome group of people you are, to be taking the time and sharing all this technical detail with us. It gets me excited about doing my own EV conversion again (I've done one in the past), but this time using AC electronics. (Unfortunately, I'd still be limited to lead-acid batteries.)

I'm looking forward to the day when all our cars will be electric, thanks to pioneering work such as yours.

Roland Crane

8:21am | 10月 19, 2006

Need help in Seattle? Give me a shout. Would love to work with you guys to help establish a market in Washington.

Lots of green thinking up here, and a fair amount of money.

jeffrey watson

8:58am | 10月 19, 2006

Any plans to offer a Tesla kit car?

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Editor's Answer: Currently there are no plans to offer a conversion kit. Take a look at this blog post.

busybee64

9:11am | 10月 19, 2006

Meanwhile, GM plods on with its hydrogen fuel cell plan. This article gave a preview of the Sequel, a hydrogen fuel cell SUV.

It notes that the Sequel feels "reasonably peppy; acceleration is smooth and nearly silent. And it is capable of reaching 90 miles an hour".

The range is 300 miles. But here's the kicker. it weighs a whopping 4,700 pounds! Despite the fact that the body is aluminum and front fenders carbon-fiber. All this for a vehicle that is small by SUV standards (197" sport wagon that seats four). Gawd!

The challenge (or one of many) is that it must fit 3 substantial hydrogen tanks underneath the chasis that operate at 10,000 psi.

Here's another interesting thing. The car also includes a rectangular pack of lithium-ion batteries under the rear seat area. Umm, good idea!

They plan to deploy a fleet of 100 next year. And apparently make the debut fully validated for productio in 2009. Given their complaints about the lack of demand for the electric vehicle, I wonder what excuse they will give to keep working on development of hydrogen fuel cells when they find nobody will want to be bothered buying these. Oh, I know. How about another government contract to revisit the electric idea.

Lance Morgan

11:02am | 10月 19, 2006

I just wanted to let you guys know what a great job I think you are doing and how excited I am about your vehicles. I have followed electric vehicles for a while now, particularly what AC Propulsion has done and I have always loved your roadster's forebearer, the Lotus Elise. I only wish that I could afford your car right now. I hope that the roadster will still be available when I finally have the money to buy a dream sports car, because that's it!

I would also like to say that I really enjoy the background/color scheme of your site as well. Perhaps you could split the difference and provide a link at the top to "print friendly" version of the site that would be a little easier on the eyes for everyone else.

Tony Belding

11:38am | 10月 19, 2006

A minor correction on the GM (or Chevy) Sequel. . . GM are going to put 100 hydrogen fuel-cell cars on the road next year, but they aren't the Sequel. They are going to be a much less advanced vehicle called the Equinox -- as far as I can tell, simply a conversion of the current Chevy Equinox as shown here: http://en.wikipedia.org/wiki/Chevrolet_Equinox

My understanding is that the Sequel itself will never see production: it will merely be used to develop further technologies. I personally have some qualms about those 10,000 PSI fuel tanks. If those ever ruptured, you'd be in orbit.

The Telsa Motors mission statment and timing to market is right on.
I enjoyed reading the whitepapers too. We are on the same page.
Mark Fleming
Xtreme Cars and Stars
Las Vegas, Nevada[Contact details deleted]

Dean

12:30pm | 10月 19, 2006

I like black bacground.

For those who don't like it, I have a solution:
1. Install Opera
2. Select View -> Style -> High Contrast (B/W)

Voila, Black text on white background.

Jobst Brandt

12:47pm | 10月 19, 2006

From what I read here, I see that AC railway locomotives seem to use similar technology, except that the railways already did this many years ago. Typically, TGV trains run under overhead current of 25kv/50Hz, 15kv/16.66Hz, 3000DC, and 1500DC as they travel across European railways, converting these to variable frequency three phase AC that drives the traction motors. As I understand it from the literature, the solid state converters were developed in France. What is different about Tesla Motors?

Jobst

marcel

1:50pm | 10月 19, 2006

Martin,

What's the frequency of the motor when it is running at 13000 RPM?

Mark Hanson

2:32pm | 10月 19, 2006

You guys continue to amaze me. Keep up the great work!!
I am hoping you can answer this, or point me in the right direction if I missed it:
What type of outlet do I need in my garage to power up my Tesla (once I get one:))?
I am building now so it would be easier to get the spare electrical needs in place now.
Standard 220 volt?
Please let me know so I can be ready.

PS I like the black background as well. Although perhaps an option would work for others?

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Editor's Answer: You can find info on charging in the FAQ and on the Charging and Batteries page. If you have a 220V outlet in your garage, it could be used for the EVSE.

How do you recharge it?

Unlike EVs of the past, the Tesla Roadster has a built-in battery charging system that can basically plug into any outlet. The car ships with a particularly easy-to-use connection system that is installed in your garage by a qualified electrician. There is also an optional mobile charging kit that allows you to charge from any available electrical outlet (110V or 220V) wherever you happen to be.

# marcel wrote on October 19th, 2006 at 2:50 pm
# Martin,
# What’s the frequency of the motor when it is running at 13000 RPM?

You need to ask Kenneth :)

RDE

7:06pm | 10月 19, 2006

re The Black Hole---everyone knows that no light can escape from a black hole. The jury already gave its decision several years ago. People who do internet marketing -- ie make their living selling information on the Web--- ran countless comparison studies of the "stickiness" of web site formats, and found that people will not tolerate white text on black backgrounds and will click away at the first opportunity. If this were a site selling diet products or the like it would increase its sales by 50 to 100% merely by changing to a white background.

This site is unique in that it is the home for rabid fans, has no competition, and doesn't have to make it's living convincing skeptics to buy something. That doesn't prevent it from being the worst example of an unreadable web site I have ever seen.

T.J.

7:48pm | 10月 19, 2006

Tesla should be planning a zippy dealership design for when the sports sedan comes out- I haven't seen one (zero,zilch,nada) that really makes it-here's the chance to stand out again.With only 2 car models, they could make a compact building design, compared to most dealerships: "the Starbucks of the auto world " in that regard (?). Maybe one pavillion ("in a plaza"-and turned, like 25 degrees-not straight-on to the street) for the showroom, another for service-separate buildngs-not connected with the usual dumb car cover / breezeway between showroom & service. Make it a solar building, of course, take the flooring right out into the plaza, all the glass tilts up so the whole showroom can be indoor/outdoor or combo. Put some nice plantiings around it -for a halibuting change, and maybe a planted earth roof (solar on the service bldg. roof, earth on the showroom pavillion?). I could see a core area (for back office, restrooms,lounge,etc.) made of rammed earth-which can be quite "earthy" looking and a counterpoint to the lightweight metal/ glass of the showroom-and thick rammed earth walls would be good place to throw some big swaths of paint color , while leaving alot of it of it uncolored.Add zippy metal wall panels of some type(s), maybe a light wood wall panel area inside (like beechwood, going right down a wall and turning into a floor area)-a small floating mezzanine cantilevering out from side wall and looking down into mainspace (and cantilevering out into plaza as entry canopy too-cutting thru a corner of the pavillion, off centered maybe). Make roof "up there" a little extra high: building becomes it's own "sign"-looking like some kind of dramatic art pavillion instead of a " business building as usual". With the unique running gear and probably chassis, should have a real "exploded car" display maybe low down on the rammed earth wall , hanging out of the wall, at an angle. Might as well do it all right, for once in the auto world, and make a buidling really as unique as the cars. Could make it all precisely detailed (but not cold) & "pre-fabable" -except rammed earth part.With just the 2 cars to sell, buildings would have a smaller, user- friendly scale to them.But, if extra land, could always add a third linked pavillion one day. Tesla should be looking at this now, so when sports sedan comes out they've got a truly spectacular "dialed-in" facility to display their likewise cars in.

flabby

9:44pm | 10月 19, 2006

-RDE wrote on October 19th, 2006 at 8:06 pm
-re The Black Hole—everyone knows that no light can escape from a black hole. The jury already gave its decision several years ago. People who do internet
-marketing — ie make their living selling information on the Web— ran countless comparison studies of the “stickiness” of web site formats, and found that people
-will not tolerate white text on black backgrounds and will click away at the first opportunity. If this were a site selling diet products or the like it would increase its
-sales by 50 to 100% merely by changing to a white background.
-This site is unique in that it is the home for rabid fans, has no competition, and doesn’t have to make it’s living convincing skeptics to buy something. That doesn’t
-prevent it from being the worst example of an unreadable web site I have ever seen.

I've never had a problem with the site colors - never even thought about them until RDE mentioned it. But now that I've thought about it, I sort of like the white lettering on a black background (especially with the red border). My two cents worth. Maybe Tesla could offer an option for you to switch to a white background if you chose. Maybe they could include other backgrounds as well, like rainbow...or pink with purple pokadots!!!

By the way Martin, thanks for this blog. it answered a couple of questions of mine.

Nice discussion on the motor technology and manufacturing problems. It's great to see a group of engineers taking parts from different designs and combining them into a better product. It shows that major improvements don't always come with new technology.

Good artical. It's nice that you take the time to explain the reasoning behind what you do. I'm looking forward to the lower priced versions when they come out.

Greg Woulf

10:10am | 10月 20, 2006

I understand the reasoning behind not having in-wheel motors in the roadster. Performance and handling and all, and I won't be disapointed if the Sedan is the same single motor configuration.

I wonder if this AC adopted motor technology is transferable to in-wheel motors, whether in a Tesla, or a different platform.

I keep trying to find out as much as I can about in-wheel technology, but I don't see a quick answer to the question of whether you could have a variable volt in-wheel non-permanent magnet motor.

Nathan

11:14am | 10月 20, 2006

Please do not change the website background. Many fine things need a bit of style to set them apart.

Anatoly Moskalev

12:05pm | 10月 20, 2006

I think I know part of the answer for the question from Jobst Brandt few posts above. Power per unit of weight of asynchronous electric motor ( the kind used in Tesla Motors car ) is critically limited by heat produced inside motor rotor. This heat is determined by specific resistance of conductive material used for rotor. It is well known that copper has that specific resistance significantly lower than other metals. So copper rotor would improve power per unit of weight significantly ( I guess 1.5 to 2 times ).
Unfortunately copper in its pure annealed form (most conductive) is very soft metal mechanically. But most highly conductive part of a rotor has to hold biggest mechnical stress because forces from electromagnetic field are applied mostly to areas in rotor with highest current. So making mechanically robust rotor from soft metal trying to minimize its mass is a real challenge. It could be managed by complex structures but they would be difficult for mass production.
Anyway I was sirprised to learn that nobody knows how to mass produce copper rotors so far. This fact alone is a vivid indication how little attention industry puts so far in developing electric vehicles.
So having such a light but powerful electric motor in fast accelerating electric vehicle is fairly important to offset unavoidably large battery pack weight. Using Li-ion batteries also helps I guess. This somewhat explains to me why nobody else so far tried to penetrate electric cars market from high end requiring fast accelerating cars.

I agree with Tesla Motors engineers that Li-ion batteries are the best choice today considering energy density and cycles life needed for practical mass produced car. I also consider idea of using batteries with extremely popular form factor from electronic industry very wise decision. Electronics will continue to push energy to volume and weight efficiensy, cycle life efficiensy and cost efficiensy. So whatever battery chemistry or ultracapacitor or any other electricity storage tecnnology comes winning it will surely be put into mass production of small 18650 batteries and they will quickly end up inside Tesla Motors battery pack with very little investment from Tesla itself.

Unfortunately current balance of battery cost (~$20000 for ~250 miles range) cycle life (~500 cycles) and energy capacity (~50 kWth) corresponds to approximately $20000 / 125000 = $ 0.16 per mile of battery degradation and $0.02 per mile of electricity ($0.10 per kWth rate assumed). This means that all the discussion about how cheap is energy for the car and how it could be offset by solar power relatively insignificant from a rational point of view. It could be iconic feature but it makes little sense in terms of cost of driving because battery degradation cost way offset electricity cost.
Also Li-ion batteries are well known for the feature of degrading just by time without any use. So with little driving battery would degarde much faster per mileage. I think typical degradation time would be 3 to 5 years. In case of 10000 miles per year driving it could correspond to as little as 30000 miles per battery pack range.

So my opinion is that Tesla Motors roadster is a very balanced and even economically sound proposition because such car use model expected is faily intensive driving and competition would be cars with ~10 miles per gallon efficiensy. In this case cost of driving is surely competitive. Other factors of car appeal would most likely be attractive enough for at least 1000 cars a year market. So as a start-up Tesla Motors appears to be successful.
But for car segment under $25000 price (real mass market for most of people) cost of driving would be way too high because competition would be against ~10000-20000 miles per year usage and at least ~30 miles per gallon efficiensy. In such a case battery degradation cost likely corresponds to range lower than 60000 miles over battery pack lifetime making battery degradation cost about $0.33 per mile or ~$10 per 30 miles. Such cost appears much higher than any gasoline car related cost was so far.

I am afraid that regular customer of cars would be mostly concerned with cost of ownership of the car. So such a high cost estimate per mile coming from battery degradation surely kills the idea of electric vehicle for masses as I can see so far. (Plug-in hybrid cars are in the same spot also.) My conclusion is that electric cars for a long time would be cars for elite. They would distinguish elite from regular people way more distinct than gasoline car. So servicing elite with expensive cars would be a destiny of all electric cars manufacturers at least for next 10 years or even more.

I do not see any near term hope for electric energy storage considerable improvement (at least 4 times in cost per mile units). Nothing new at least to my knowledge goes in battery chemistry promising enough for dramatic cost reduction or energy density or cycle life improvement. As for ultracapacitors EEstore patent claim for energy density of ultracapcitor approaching batteries it looks realistic only for a first glance. But what the patent does not take into account is saturation of dielectric material at high electric fields because inducted polarization field cannot exceed intermolecular electric field of chemical bonds of material itself. So it is most likely that final electric energy density would be ~100 times less than claim. This would make a significant improvement in ultracapacitors area itself (very decent result anyway). But this would be way short of required energy density for electric cars.

So my opinion is that for under $25000 cars market for next 10 years viable choice would be to use electric drivetrain similar to what Tesla Motors have but use ultracapacitor to absorb power peaks of acceleration/deseleration and high efficiensy internal combustion engine (ICE) for 10 - 15 kWt to maintain sustained car run. It might be viable to consider Stirling engine for 10 - 15 kWt if design expences and infrastructure building expences for such an engine mass production could be realistically invested. Ultracapacitors have very high recharge cycle count so cost of capacitor degradation per mile would be insignificant. Regenerative braking would be enabled and ICE engine would be running at much higher efficiensy than typical because of no power peaks on it. Use of Stirling engine may increase overall efficiensy of energy use even better. Cost of electric drivetrain and ultracapacitor would be offset by fuel economy, removal of gearbox and lower price of smaller ICE engine. Electric drivetrain would allow all nice features of traction control, fast acceleration etc even for low end car.

Anyway appearance of Tesla Motors on the Internet make a hint for me to learn a lot about electric cars and solar energy recently. So thank you guys for a blog and other actions you doing to promote your technology.

Herr Scholz

12:55pm | 10月 20, 2006

The Tesla Roadster is a toy. What about an affordable, electrical driven, "everydays", compact car?

Fast forward to the time after White Star is released, and the ICE automakers and oil companies are feeling the pressure. What do they do? Buy out Tesla? Start investing heavily in electric utilities? Do the carmakers work out a deal with the oil companes to basically GIVE customers a gasoline car, and make back the money on some kickback they get from gasoline sales? Do they start hiring the EV industry movers and shakers away, and get serious about their own EVs?

I have to imagine that the Tesla roadster is going to cut into the Lotus sales of that model somewhat. I guess Lotus must make enough money off of the sales of the Tesla chassis to consider it incremental business rather than competition.

Including "600V IGBTs". This blog page compares the Tesla motor to the EV1 motor. How does the Tesla motor compare to this Ford/Siemens/Ballard system? I know Tesla's produces at least twice the HP...

stan

3:06pm | 10月 20, 2006

I don't understand all the technicals, but I really appreciate the research and the custom development of your own motor base on Tesla's. This really makes me respect the Telsa name now that I know it is tied to something instead of a cleaver marketing image connection. There is a direct connection to Tesla like dna for the heart of the Tessla line of automobiles yet to be born.

Please tell me what type of materials are used in the frame and body of the Tesla Roadster. I am having difficulty finding this information in your website.

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Editor's Answer: The body is carbon fiber and the chassis is extruded aluminum - take a look under ths skin.

T.J.

6:22pm | 10月 20, 2006

Moskalev has a point on the battery cost. Cost of driving over life of batteries vs. cost of driving an average mileage ICE car might about equal out to be same. But maybe in 2-3 years battery tech. will improve. Irregardless, I heard Tesla Sports sedan will sell for near $50,000 (true?)- so like he says, it's a " higher middle"/upper middle class car- but then there's a lot of people in that group. Anyone going to the trouble of getting solar on their house is going to have some extra cash to start with. Phase III would be the Tesla Sedan at $30- $35,000 max. If the sports sedan is 2-3 years out, this next car could be another 2-3 years out (?)-by that time there could be signif. advances in battery tech. and/or lower costs for lithium-ion (?) In any case, for me it's the principle of the thing-I'll pay more for a zero co2 emission EV (via solar power) car because it's the 21st century , time to get the halibut on with it for a change-particularly as far as this country goes. It's a clean job, but somebody's gotta do it. Eventually the $25,000 "sensible" EV car will be there-if it even takes 10 years-via trickle down from the top: the Tesla Roadster.

Go for it guys! Between electric and Hydrogen power....end global warming.

s.g.

Richard

7:18pm | 10月 20, 2006

Is 3 phase power anything like the 8 phase power on my Asus motherboard? I understand the concept of 3 and power, but I am not quite sure what a phase is, so if you could clarify it for me, that would be great.

David Hunter

7:28pm | 10月 20, 2006

It would certainly be interesting to know what the expectations are in terms of a reasonable service life of the vehicle, assuming periodic battery changes. Seems like it should last longer than a typical ICE vehicle, although nothing lasts forever. It would be very interesting to see total cost of ownership comparisons with similar performance ICE vehicles, across the expected typical service life, for different annual mileage profiles. Of course in the end it's still apples to oranges, and even if the Tesla was more expensive overall, there'd still be a market of people who are willing to pay for it. The wind-generated electricity that I buy from my local utility isn't as cheap as the nuke/coal power that they'd otherwise generate for me, but wrapping in the externalities makes it seem like a very reasonable investment, in my mind. The shared environmental and national security costs of burning gasoline are a lot higher than the pump price in the USA. Thus, I've already told my wife to start planning for the purchase of white star, once it's available and validated by production use of the roadster...

T.J.

10:35pm | 10月 20, 2006

Looks like the motor in the Tesla is small enough to work well in a motorcycle. Tesla could follow BMW & Honda-BMW makes some nice cycles, do what they do with their shaft drive.Plenty of shops out there putting out custom cycles-get with one of them. Do carbon fiber, aluminum or stainless steel (or combo?).

Malcolm Wilson

12:52am | 10月 21, 2006

So...............

All I have to do is buy a Europa, buy the AC-150 Gen 2 Drive Train from AC Propulsion and then somehow get hold of a Tesla BMS/battery pack and I can build my own UK-legal Tesla-clone.......... :)

CHRIS

4:56am | 10月 21, 2006

NEW SOLAR POWER BREAKTHROUGH CAN SUPPLEMENT (ON VEHICLE) TESLA'S VEHICLES: AS AN ENG. STUDENT FROM SOUTH AFRICA I MIGHT BE OFF THE MARK HERE, BUT IN MY LOCAL NEWSPAPER (CAPE ARGUS, FRONT PAGE, 11 FEB, 2006) AN ARTICLE ENTITLED "SA SOLAR SCIENTISTS PUT THE REST OF THE WORLD IN THE SHADE" A TEAM LED BY PROF. VIVIAN ALBERTS AT THE UNIVERSITY OF JOHANNESBURG HAS DEVELOPED SUPER EFFICENT PV'S. (DO A GOOGLE SEARCH ON: VIVIAN ALBERTS TO FIND ALL OTHER WEBSITES) THIS TECHNOLOGY "HAS BEEN PATENTED ACROSS THE WORLD" AND IS 5 MICRONS THICK (A HUMAN HAIR IS 20 MICRONS THICK) THEREBY MAKING IT MUCH CHEAPER THAN SILICON PV'S (LESS MATERIAL USED). ACCORDING TO OTHER SOURCES THE SURFACE AREA OF A LIVING ROOM OF THESE PANELS CAN POWER AN ENTIRE HOME. WEEKEND ARGUS SAYS TV'S, FRIDGES, COMPUTERS, EVEN GEYSERS (HOT WATER CYLINDERS). SA DOESNT HAVE INFRUSTRUCTURE TO MASS PRODUCE SO HAS PARTNERED WITH GERMAN GIANT IFE SOLAR SYSTEMS WHICH WILL INVEST R500 MILLION & PRODUCE IN GERMAN PLANT. MY EXPERIENCE OF AMERICAN OPINION HAS BEEN OFFISH TO SAY THE LEAST. THIS IS A RESPECTABLE UNIVERSITY (NOT PRIVATE) PROFESSOR NEVER MIND SHADY BUSINESSMAN, ETC. ANYWAY SOME SAY NASA IS USING THESE SAME PANELS WHICH ARE AS GOOD OR BETTER, BUT THIS I DOUBT SINCE ALBERT'S ARE "PATENTED ACROSS THE WORLD". EVEN IF THEIRS ARE DIFFERENT BUT AS GOOD OR BETTER THEIR TECHNOLOGY HASNT TRICKLED DOWN FOR VERY GOOD, PROBABLY POLITICAL, REASONS. CLOSER TO MY POINT: I THINK TESLA MOTORS SHOULD PARTNER WITH IFE SOLAR SYSTEMS TO ENCORPORATE THEIR SUPER EFFICIENT SOLAR TECHNOLOGY INTO THE ROOF, BONNET (HOOD) & POSSIBLY SIDES OF ALL TESLA VEHICLES TO DIRECTLY SUPPLEMENT THE MOTOR (BYPASSING BATTERY) ALLOWING LONGER BATTERY LIFE THEREBY REDUCING THAT PROBLEM. ALBERTS PANELS ALSO, ACCORDING TO THIS ARTICLE, "CAN OPERATE ON ALL FLEXABLE SURFACES" PRESUMABLY DUE TO ITS THINNESS. LOOK HOW HOT YOUR HOOD OR CAR ROOF GETS ON A HOT SUMMER DAY: HOT ENOUGH TO FRY AN EGG! APPARENTLY EVEN IN SA WINTER THESE PANELS ARE GOOD ENOUGH TO POWER ENTIRE HOME (INDIRECT SUNLIGHT)

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[Editor's comments: Thanks for the thoughts. It is easier on the eyes if you refrain from using all-caps.]

CHRIS

5:32am | 10月 21, 2006

It always amazes me how people carelessly say that the motor industry might eventually come up with something as good or it hasnt already because they just dont think out of the box, etc bla bla bla. It never occurs to them: why dont they produce 0% emmission vehicles or close to that so that customers will buy their cars like hotcakes & they'll make a fortune?, gee let me think, very possibly because the very same people own the oil industry, or some similar scenario. Do you really think that with their huge financial & infrustructural rescources they really just don't think "out of the box"? Their newest technologies just dont meet the under 40% or thereabout emmissions standard, and they continue to promote clean, but inefficient hydrogen refined from coal oil, etc. whom they or their buddies control. Maybe they just don't want to think 'out of the box' and want us all, at least partially, to be dependant on their rescources (oil etc.) AMERICA (& ENTIRE WORLD) WAKE UP !

Peter J Hedge

7:03am | 10月 21, 2006

What happens when the driving range of an EV is exceeded? Does it some to a sudden stop as would a ICE vehicle or does it slow down until its batteries are completely drained like a flashlight or electric drill?

Joshua Mize

7:56am | 10月 21, 2006

History is full of big, powerful companies being comepletely overthrown, out of no where by smaller companies they thought were insignificant. The car companies act like Tesla and other EV companies are not a threat...but I think they are wrong, and I do think they will be mowed down very soon. We've reached the tipping point.

Greg Woulf

8:09am | 10月 21, 2006

To Richard:

There's a pretty decent explanation of phases back a few replies.

In a nutshell is just means that the magnetic force that spins the shaft comes from 3 different locations around the edge of the circle of spinning components inside the motor.

A one phase would push every time a spinning electrified component passed by, like a dad standing still and spinning the playground merry-go-round wheel at every pole on a playground spinning wheel. A two phase motor would be like a mom and a dad on opposite sides both spinning the wheel at every pole, and a three phase would be a 3rd person spinning the wheel at every pole standing stationary somewhere opposite the othe two.

Roger L.

8:39am | 10月 21, 2006

#David Hunter wrote on October 20th, 2006 at 8:28 pm

#It would certainly be interesting to know what the expectations are in terms of a reasonable #service life of the vehicle,.....
__________________
I was just thinking the same thing as winter is approaching here in the upper Midwest... 'tis the season of salt and sand on the roadways for about 4 months. My "perfectly good" 1989 S10 pickup with 220,000 miles on it runs like a watch but the body has severe rust to the point of embarrassment of my wife (if you know what I mean). But, with the carbon fiber body of the Tesla roadster, and possibly the White Star, there'd be no rust. Hence, the body could last "forever"! That, and other factors already mentioned, would have a significant impact on service life. I too would like to see a thorough analysis of cost of ownership. (I'm too lazy to do it myself.)
On the other hand, how will we justify buying a new car if the old one isn't falling apart?

Wolfgang

8:40am | 10月 21, 2006

Asynchronous "squirrel cage" AC induction motors running off frequency inverters have become the standard drive system in industrial automation over the past 15 years. Up to about 250kW these are very cost effective and of course virtually maintenance-free. Modern flux vector control algorithms achieve outstanding torque/speed characteristics. AC drives consume the largest portion of all electricy for industrial use. This has sparked an initiative to increase efficiency levels, which have been designated EFF1...EFF3 in Europe.

Strangely, efficiency numbers posted as 80...90% for the Tesla Roadster's motor are less than exceptional in relation to those ratings. Energy efficient AC motors can be ordered today from numerous manufacturers with efficiency above 95% for full load of 200 kW (see for example http://www.drives.co.uk/news/uknews/news_uknews435.htm). I suspect there must have been other considerations such as mass, size, maximum rpm, integral gear, etc, in TeslaMotors' own proprietory motor design. Another factor may be efficiency at partial load. So possibly there is some future cost saving potential in sourcing a commerically available high efficiency motor. It might also be feasible to further increase efficiency in the AC motor itself, as well as by ditching the two-speed gearbox.

That said I'm very impressed with TeslaMotors' concept, and your roadster's sleek looks. Have lots of success in the years ahead.

Ronald Greene

11:30am | 10月 21, 2006

The A.C. motor is vastly superior to a D.C. motor. Telsa worked for Edison and saw the shortcomings of D.C. which would have been a
disaster for the U.S. if Edison had succeeded as it all would have to have been thrown out. For example, when a light shorts out
with D.C. current the short welds together and burns all the way back to the generator setting the building on fire and all the cable then
also had to be replaced. Thus, when Telsa designed the A.C. motor he rotated the electromagnetic field so that the motor would have time to cool and thus an A.C. motor can do much more work without overheating. The EV 1 went Telsa one step better by using a water cooled
A.C. motor and I am surprised that you didn't follow suit since you need to cool the batteries anyhow. Further, you could use the heat
to cut down on the current draw in the winter for the heater. Also the EV 1 with the electronic speed limiter removed set a land speed record
of 184 miles per hour which most people do not know and you are not going to do that without a water cooled A.C. motor. Copper rotors
are very soft and how you guys keep it from from coming apart at 13,000 rpm is an interesting question and another reason why I like
water cooled A.C. motors. General Motors and the oil companies seem determined to stick us with fuel cell cars which will be heavy,
too complex and refueling with high pressure hydrogen is not going to be fun because it will leak. Anyway, I hope you guys win because
fuel cell electrics will be as bad for America as D.C. electric would have been.

Of course your first 100 vehicles would only be stolen by morons, but eventually they will not stand out so much.
Thinking that far ahead, somewhat with any EV but especially one with a one-piece integrated-battery-pack,
it would seem trivial to embed a LoJack so that even fully knowing the design, to disable it will be beyond the
means of the casual thief. The weak point would seem to be the antenna - would it be worth the trouble to
do something coaxial with the massive mounting hardware, so the only way to get to the LoJack antenna
is to dismount the battery pack ?

# Peter J Hedge wrote on October 21st, 2006 at 8:03 am
# What happens when the driving range of an EV is exceeded?
# Does it some to a sudden stop as would a ICE vehicle or does it slow down until its batteries are completely drained like a flashlight or electric drill?

In general, it depends on what the control electronics decide to do.
My EV starts to turn on various warning lights, and reduces the power, leaving you in "limp home" mode as the last of the charge is used up.

BSS

7:48pm | 10月 21, 2006

Several of my questions have been answered by this post. Thanks, Martin! Anatoly brings up my main concerns with regards to further development. Batteries, batteries, and batteries (and maybe the lifespan of the PEM). Based on the $20,000 figure, at an optimistic 150,000 mile range, that is $0.13/mile. Add in $0.02/mile for electricity, and you are at $0.15/mile. Assuming a reliable PEM, the reduced maintainance costs might be around $0.04-0.08/mile and $3.00/gallon gas at 30 mpg for the ICE equivalent, or $0.10/mile, and the cost is $0.14-0.18/mile, right around the Tesla. Since gas IS going to increase in price again to at least this level, the Tesla could be worthwhile if you drive alot (20,000 miles/yr or more). However, if the Altair Nano batteries are for real and can be produced at a similar cost, the lifetime could be extended to 20 years or more, reducing battery cost to $0.03/mile with similar car efficiency (the batteries might be a little heavier though the cooling system and protective packaging could be eliminated), reducing costs to $0.05/mile, or 1/3 the cost of the ICE. Of course, the lithium and cobalt production would have to keep up. And, most importantly, the Altair Nano can be recharged in the 10-15 minutes necessary for wide spread adoption of EVs. I'm not sure that I would want one if I have to invest $20,000 every 5 years to keep it moving, regardless of how much I drive, due to the shelf life of lithium ion.

As for LoJack, it shouldn't be necessary. Since the car depends on computer controls a pass code is required, so unless the thief brought a flatbed tow truck with a strong winch or a really good computer hacker, driving away with the car would be impossible. I believe this is already planned for the Roadster, and a fingerprint ID could easily be added if not already there. Plus, you could add things like speed controls for certain users (like a 16 yr old son?). If the Tesla can be economically made, the car as we know it will be revolutionized. Of course, if Detroit could deliver "outside the box", this could already be a standard feature on today's ICE cars.

One more attempt to explain 3 phases and Tesla AC motor operation for whoever interested because it appears to be unclear to some participants:

The point is to create magnetic field perfectly rotating incide the motor. So if you imagine the field as a needle perpendicular to the axis of rotation and look from a side while it rotates you would see apparent length increasing and decreasing and the apparent direction of the needle would alternate. That is exactly how current through a single coil (corresponding to a phase) behave. It creates a projection of the "needle" of a magnetic field. But as it is not possible to fully comprehend the true position of the needle from just one projection rotating magnetic field cannot be created by one phase only. At least second phase is needed to create additional projection. In fact for a smooth ride it is better to have 3 projections from directions of view 120 degrees apart. From such needle projections it is possible to derive true position of the needle inside the motor for every angle of its rotation. That is exactly how 3 currents in at least 3 separate coils would oscillate to create a rotating magnetic field of a real motor.

If you imagine for simplicity a permanent magnet like a compass needle inside the motor perpendicular to rotation axis it will rotate following the magnetic field - just the torque would be much stronger because of much stronger magnetic fields involved. Some AC motor designs in fact use permanent magnet as a rotor but it is costly and also overheating could kill the magnetism inside such a rotor. Tesla invented another principle to create such a rotating magnet inside the motor. You can make the rotor from a good conductor of electricity (basically any metal would be OK but silver would be the best - just too costly, copper is second best). While rotating magnetic field would move relative to this rotor it will induce electric currents inside that metallic rotor - basically the same way as all electricity generators produce electricity. These currents would behave as if a needle magnet is placed inside the motor as described above. This induced "magnet" would be proportionally stronger the faster magnetic field rotates through the rotor metal. Such a relative rotation of magnetic field through the rotor is the "slip" in Martin's original explanation. So the overall picture is that you have rotating magnetic field moving faster than rotor itself rotates followed by a rotor rotation. This would cause rotor acceleration (electricity consumed). For deseleration you make magnetic field rotate slower than rotor rotates (electricity produced back to battery). The torque inside the motor always tries to make rotor rotates in sync with magnetic field rotation. But the torque would reduce to virtually zero if that syncronous rotation would emerge.

I believe I provided fairly accurate qualitative picture of inductive AC motor operation with 3 phases. By the way by education I am a scientist in physics so I know this stuff to a certain degree.

sprky777

12:44am | 10月 22, 2006

I know the cost of metals is very high, but silver has lower resistance than copper and would generate less heat. Also, using square conductors to create a compact winding would improve energy density.

Dean

12:49am | 10月 22, 2006

# My EV starts to turn on various warning lights, and reduces the power, leaving you in “limp home” mode as the last of the charge is used up.

I see this as a big plus. There is no sudden stop as with gassoline cars. When the car is starting to 'loose power' you still have many miles in the battery.

Rich Anderson

5:25am | 10月 22, 2006

Keep up the Blog, Martin & JB! I've learned much. Been a Nicola Tesla fan since High School (1967). It's obvious that one of the keys to inexpensive Tesla cars is battery cost. I have high hopes that LiS or nanotechnology will solve the cost, weight and effeciency problems. A parallel charging system would halve the charge time and split the load to 2 circuits. (Another factor for a rapid charge standard for future charge stations). Contract a hotel chain to put a charge station in each of their hotel parking lots would boost sales and standardize chargers.

I'll be one of the first in line for a 500 mile range $25k Tesla sedan with a

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Editor's Comment: This blog software allows embedded tags. Thus, if you use a "less than sign" in your post, it will get "interpreted" and results in the post getting truncated. If you would like to post again without the less than sign, I will delete this truncated post.

Paul

12:53pm | 10月 22, 2006

It is a bit off topic to the afore going AC induction motor discussion, nevertheless, I would like to add just one more remark over the usefullness of a hydrogen fuel cell, compared to batteries. Major advantage would be the speed of refuelling compared to recharging, while still being 100% electric and clean. Having read about the ineffiency of water electrolysis as a way to produce hydrogen it is clear that electrolysis is not the way to go, nor using natural gas (or other fossil origins) as a source. So, find better ways! One sustainable alternative might be photocatalytic water decomposition, thus generating hydrogen (&oxygen) directly from sun light. Once practically feasible, this may become an alternative next to the PV-cells. For more info, search for 'photocatalytic hydrogen'. Of course, other issues like energy intensive compression of the gas and its save distribution need to be solved as well, but technology is progressing steadily. Something to look forward to!

I love how you detailed the practical every day use of a sub $30,000 car that everyone could afford however, dont forget that battery technology is right now taking a complete change. With the new Toshiba Nano-Cell battery comming to market, the hypothetical "Tesla Sedan" would more then likely move to this battery technology. This would solve the battery charging problem of 3 hours down to 3 minutes and solve the issue of battery degradation. These have been rated at over 1000 charges with almost no loss of capacity. People, this is the future if you like it or not as soon as the corporate partnerships beging to unvail! Just watch out for the evil oil industry. They will do anything to stay in business and with their billions, im sure they will toss their perverbial wrench into the gears.

Tesla, could you give us any insite into the future if you plan to possibly use this battery technology???

Moskalev: Say what!?: "what we have here is: failure to communiate!" ( as Strother Martin said). We need a fancy 3-d , computer- generated graphics, spinning, multi-colored, streaming , detailed video model of this thing to really get it. A picture is worth 1000 words-no kidding in, this case. I did well in college physics, but this is why I never made it my job, like you! You guys get it the first time-I'd get it, but more like by the sixth time! -unless I was back in school, then it might be the third time!

Joe King

6:22pm | 10月 22, 2006

Tesla Motors is out of touch. Who the hell wants to pay $100,000 for an electric car. Just buy the Toyota Prius and alter the battery pack and there you have it. An electric vehicle that can run 400 miles before recharging. It is quite easy to alter the battery pack on the Prius. Just go to Google.com and search for "Prius alter batter instructions".

The variable frequency drive system, implies that with increased frequency, increased rpm results. If so, does the system have a max rpm? A DC motor can be made to try infinite rpms (as I once learned in a EE motors lab). Your max rpm (speed) may be limited to power requirements (based on load, ie. aerodymamics, weight etc.). If so, is top speed a function of the weight of the driver?

If the driver is 100 pounds, do you require flaps and rudder?

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Editor's response: The Tesla Roadster redlines at 13,500 RPMs. For more information, see our performance specs.

##ME> My EV starts to turn on various warning lights, and reduces the power, leaving you in “limp home” mode as the last of the charge is used up.
# Dean wrote on October 22nd, 2006 at 1:49 am
# I see this as a big plus. There is no sudden stop as with gasoline cars. When the car is starting to ‘loose power’ you still have many miles in the battery.

A Toyota salesperson told me that the Toyota hybrids will limp to the gas station on pure electric if you ever run out of gasoline...
(Although the puny battery pack in those cars probably only gets you a couple of miles of range on electricity only, and Toyota recommends against taxing the batteries in this way)

I had an Rx7 years back that I converted to run on propane. There was no fuel pump as the tanks held pressurized liquid. When the tanks were running low the pressure would drop and the car would start to produce less power. I liked that sort of "dimming effect" to the power rather than the all or nothing you get with a gasoline car. Many gasoline cars have a warning light that you are almost empty. They could easily change it to tell the engine ECU to retard the ignition or limit your RPMs to make it very obvious that the end is near.

"Back in the day", cars had real "reserve tanks" . The fuel gauges were so inaccurate that you would drive until the car started to sputter, then you would flip to the reserve tank and head for a filling station.

# Paul wrote on October 22nd, 2006 at 1:53 pm
# I would like to add just one more remark over the usefullness of a hydrogen fuel cell, compared to batteries.

I am sorry, but I just don't see hydrogen as a viable fossil fuel replacement source unless someone manages to make a workable fusion reactor.

TeslaMotors was right to focus on battery powered EVs, and push to get more PV cells installed as a source of power for them.

Major breakthroughs in batteries and photovoltaics are coming fast, while hyrdrogen fuel cells seemed doomed to slow progress.

Josh

4:16am | 10月 23, 2006

The write up on the AC Induction motor is good, but neglects one efficiency effect of using a permanent magnet synchronous motor. Regenerative braking, which cannot be done using an inductive motor. Used to produce all the electricity to power today’s hybrids, I'd think not being capable of regenerative braking would be a significant efficiency and public relations hit.

I think that the combination of the technologies in these three links is the way to go. Mitsubishi is doing good with their in wheel motor technology, I like the hollow doughnut construction that locates the rotor outside the stator. It has several design benefits. In previous posts the comment on in wheel motors has always been the increase in unsprung weight, and the resulting bad handling. That is where the bose suspension comes into play. It seems to me that this type of electromagnetic suspension would dramaticly increase the handling of a car equiped with in wheel motors. What I also like is the fact that the Mitsubishi car has it’s battery pack installed in the floor, this saves a lot of space. The last technology that would be very usefull to Tesla, is the autonomy concept from GM. Ofcourse these wankers use this beautifull concept for a fuel cell hydrogen car (dead end technology). Tesla could use the concept to build one “skateboard” frame wich houses all the technology (motors, batteries, inverter, charger, suspension) This way they CAN build and develop more than one car at a time, because every car would use the same skateboard. You would just have to design different car bodies, one of every type there is on the maket today can be done. Hatchback / sedan, estate, SUV, pick up, you name it, it can all be build on top of one ingenius skateboard design!

BSS wrote:
"Based on the $20,000 figure, at an optimistic 150,000 mile range, that is $0.13/mile. Add in $0.02/mile for electricity, and you are at $0.15/mile. Assuming a reliable PEM, the reduced maintainance costs might be around $0.04-0.08/mile and $3.00/gallon gas at 30 mpg for the ICE equivalent, or $0.10/mile, and the cost is $0.14-0.18/mile, right around the Tesla. Since gas IS going to increase in price again to at least this level, the Tesla could be worthwhile if you drive alot (20,000 miles/yr or more). "

Something missing here.
30 mpg -why that number? This Roadster is a Supercar. Why not compare it to like wheels? A Lamberferrarporcharodi 's10 to15mpg would be a better comparison number. (not to mention the luxury tax those cars have added to the purchase price)

What are the mantainence per mile numbers for a 'everyman' car? Was that mentioned?
What are the maintainence per mile numbers for a Supercar? Can you imagine what the repair costs would be if you put 150k miles on one of those finely tuned exotics?

Home Solar and Wind power can also affect these calculations as well as gasoline prices will go to 4 to 5 dollars a gallon in the next 5 years. (why?... Because they can)

e

marcel

11:15am | 10月 23, 2006

I think the output frequency of the inverter is 13000 RPM / 60 = 216 Hz.

El T.J.

6:59pm | 10月 23, 2006

Olla!-Jose King: we don' neeed no steenking Prius!

T.J.

7:30pm | 10月 23, 2006

"Skateboard" platform Robin mentions IS a great idea. Would be nice to vaccum form the whole thing out of superform aluminum-maybe glue layers of vaccum form alum. together-laminated like plywd. , thicker where needed, channel shapes built-in as struct. beams, where needed. Guess they can't do similar with carbon fiber (?). The hole car bottom area/platform would be stamped, just like a toy model car.Then attach bodies to platform using only 6 or 8 bolts-and Bam! (to quote Madden)you've got a car/truck/suv/van.

For the price, I would like to see the Roadster come with PV panels or a wind turbine for your home. The idea is noble, but pushing the responsibility off on the grid is falling short of the ideal. In the next 14 yrs, we will add 1 billion more people to our planet, the fastest rate in human history. An estimated 1,400 coal burning power plants are on schedule to be built, most without the ability to sequester the carbon released. Our worldwide CO2 output is only increasing, as is our effect on climate change. The heatwaves in Europe during the summer of 2003 contributed to the deaths of nearly 40,000 deaths in Germany, France, and Italy alone. So, it would be nice to see Tesla Motors truly aim for a "zero emissions" car that took full responsibility for how the fuel was generated.

Exactly. I've been saying this for a while. Oil companies can charge as much as they want and we have to pay for it OR find / create an alternative. The cost and risks to developing an alternative requires the price of gasoline to be high (and remain that way).

The real problem is that Oil companies have an oligopoly on the energy market. At any point they can slash prices and still make a profit. This presents an almost insurmountable level of risk to any large capitol investment in a real alternative.

If gas goes back to $1.50 a gallon, oil profits won't be obscene anymore and, like the suckers we are, we'll all forget about $3.50 a gallon and buy that new [insert name of large SUV or retro muscle car].

Anatoly Moskalev

10:19am | 10月 24, 2006

Re: to Robert on October 22nd, 2006 at 3:55 pm:

As I learned on Toshiba Web site they disconnected all Li-ion battery technology development and migrated to fuel cell solutions as electricity source for electronics. So I do not believe any battery technology improvement would come as you mentioned. As I see it now (may be it is my mistake but anyway) most prominent battery manyfacturers for electronics who developed Li-ion technology to the level it stands now are migrating into fuel cells.
One interesting approach in fuel cells for laptops I have seen is to use NaBH4 + water to NaBO2 + hydrogen chemical converter in combination with fuel cell. The idea is to get ~10 times energy capacity per unit of mass to generate electricity. Also recharging goes by cartridge replacement with some solid/liquid substance in it. So this approach sidesteps hydrogen delivery/storage problems.

I agree that some progress in electricity storage exist and eventually it will enable electric vehicles for mass market. My point is that in at least 10 years I do not see a solution with LOW ENOUGH COST to be practical for fully electric cars under $25000 price. So electric vehicles would be confined to high end auto market for at least next 10 years or more. There is nothing wrong with it from a business point of view. Just I think the hype on this blog about emerging soon mass transition to electric vehicles is way overdone.

Re: to T.J. on October 22nd, 2006 at 6:06 pm:

I was interested to train myself in explaining the principle in words - failed attempt is OK in the blog. Sure computer simulation, animated picture etc would be much better - very likely would be same failure anyway. I guess if you are interested you could take say a pen, put it on a table and look at it from a side (look parallel to surface) to see how apparent length of a pen changes while you rotate the pen. If at each angle you would look from 3 different directions 120 degrees apart round the table you would see how apparent lengths are changing relative to each other. This would be feasible to do "animation" to clarify the matter.
Anyway simpler to get explanations were provided by other folks. I just tried to paint a bit more accurate picture from real physics point of view. Obviously I failed - OK good to know.

They appear to have abandoned in-wheel motors for, shall I say, the Tesla approach, in their latest test vehicle.

William Thomas

10:31am | 10月 24, 2006

It is pity this website gets so many posts from ill-informed geeks like me.

As I understand it, the Tesla Roadster is a HOT CAR. It is designed to be a straight-up winning value proposition for its buyers. Geeks, you should cheer: an electric car without apologies, that should sell in its target market on straight performance and quality.

Go Tesla Motors! Build hot cars!!!

Anatoly Moskalev

11:00am | 10月 24, 2006

Re: to marcel on October 23rd, 2006 at 12:15 pm:

By the principle of inductive AC motor frequency of magnetic field rotation must be larger than rotation frequency of the rotor for acceleration. What you explained is lowest limit of the frequency corresponding to zero slip and zero torque. In reality to provide high torque in a small mass of a motor slip frequency have to be really high. In fact the higher the slip the larger torque per the same mass you would get. But the higher the frequency the larger heat production you get in power unit.
Typical powerful IGBT switching energy could be ~100 millijoules per switch cycle for ~100 kWt motor. So you could use ~10 kHz PWM frequency for typical ~1% losses in inverter. This confines emulated current sine wave of inverter to less than 1000 Hz frequency for sure. From the torque curve dependence versus frequency presented by Tesla Motors I could guess that torque reduction at high RPM is due to fixed upper limit of inverter frequency. In this case I could guess 216 Hz + 0.25 * max_slip = max_slip would be a viable relatinship because of 4 times torque reduction at top RPM. So we may assume up to 270 Hz inverter frequency changing in wide range from say 50 Hz to 270 Hz. But this is a very rough guess because of critical uncertainties about slip frequency used by Tesla Motors engineers.

Also by my estimates induced currents in a rotor have to be 10000 to 30000 amperes and rotor heat production should be ~1 - 2 kWt at maximum torque. This implies that some air pump have to push air along the motor axis at ~100 liters / sec speed at least. Low weight of a motor means that stator coils are reduced against optimal efficiensy making motor loose efficiensy from typical 98 % ballpark down to 90 % ballpark. Heat production pressure inside inverter and inside stator has to be higher than typical so I guess ~10 kWt in stator and ~5 kWt inside inverter. So they get ~15 kWt of heat losses for top power. Typical motor + inverter would have ~5 kWt losses for the same power.
Loss of motor efficiensy is unavoidable to reduce weight of the car to get its sporty performance. Typical weight for ~200 kWt motor I think would be 200 - 400 pounds versus 70 pounds of Tesla Motors design. Not sirprising they sound proud of the motor they created for mass production. It is the first motor I know pretending for mass production and having intense cooling fluid pumping to remove heat losses - somewhat of typical ICE cooling system but used for electric motor.

I should notice that all these observations are my pure speculations based on my knowledge of physics and some electrical engineering skills. I have no supporting hard evidence of any sort. It would be interesting for me to see really detailed specification of electrical system of Tesla Roadster but I guess it certainly could not be published because of technology secters involved.

BSS

1:33pm | 10月 24, 2006

vfx,
Actually, I compared it to an Elise, which if you check the Lotus website, gets about 29 mpg, which should average to 30 mpg if building a hybrid version. The Elise isn't quite as quick off the line (4.9 compared to 4.3). While not an exact comparison, it was intended to show that the battery could already be comparable to todays gas prices for heavy drivers if they can make the batteries last longers. It certainly wasn't intended as a hard and fast number, just a speculative number to make my point. And I agree totally, gas IS going to increase, as I said before; peak oil is real and oil sands, tar sands, and shale not withstanding, gas will eventually skyrocket, be it in 30 years (USGS) or -1 year (Ken Deffeyes, last Thanksgiving).

marcus

2:16pm | 10月 24, 2006

Hi.
This is slightly off topic but I have an idea that I couldn't find repeated elsewhere on the blog (by the way it would be great if you could google search the whole site, not just the blog). I assume perhaps that the next sedan model may be outfitted with GPS and mapping. How hard would it be to record rate of energy usage according to position? Because energy usage would depend on traffic and landscape topology (and time of day and I guess perhaps driving style) if all this data was collected over time, it may enable energy estimates to be made for planned trips so that you could be confident of not running out of energy for proposed journeys. In fact such an energy usage map could be a common resource for the whole EV community.

John McCormick

7:53am | 10月 25, 2006

To Martin and the TESLA group,

You are the first production-side advocate of EV to present not only a factual case for this type of vehicle; you provide the level of quality that made Subaru popular.

As an environmental advocate working in Washington DC on climate change issues, I have come to accept that my peer group failed to initially support -- later rescue -- the infant EV industry. Now, we have nothing to fall back upon save for visionary engineers such as yourself and the TESLA team.

I often compile energy-related data from EPA and DOE web sites to defend environmental positions, legislation and policies. ADM is of particular interest to me and that company's coal consumption figures are truly alarming. Given, some of the power and steam demand is used to process grains for other than ethanol production, it is still a huge CO2 footprint the company must reduce. Other ethanol-only companies are also subject to public criticism for using CO2-producing fuels to process their supposed eco-friendly fuels. I'd like to share some of my findings with your technicians who might share my interests in the CO2 emissions of ethanol (from the process end of the equation).

When I pay off my son's college tuition, I'll be in a showroom wanting to test drive your product.

Good luck to all of you. We need your vision, courage and skills.

John McCormick
Energy Policy Center[Contact information removed]

David

8:17am | 10月 25, 2006

A naive question on battery mechanics... I was under the impression that batteries can accept power at the same rate that they can discharge - that being the case, if the car has a 250 mile range, and a top speed of 135 miles per hour, shouldn't it be possible to charge in less than 2 hours?

great. let me know if it can run on the east coast.. Philadelphia. and how do you recharge the battery if you are out on the road on a trip.? beautiful car and am interested in knowing more about it. thanks [contact email removed]

I have been doing some reading on cars lately, and it seems to me that you guys should use an automated manual transmission, as it shifts faster than a manual tranmission operated optimally, has lower weight and shifts like a automatic transmission (except much faster with much lower weight), preventing the possibility of a Tesla Roadster accelerating to 75 mph and blowing its engine because its driver forgot to shift. Fueleconomy.gov has a webpage on Automatic Manual Transmissions:

I'm suprised there aren't more women responding to this car. This tells me two things, that women are not watching the news, and for the most part if its not in front of them to buy then they don't even know it exists. What a wonderful car, saw the news spot with the Arnold S. I thought it took awhile for MSNBC to air the story. Not only will this car sell, you'll show Harley what backorder means, because I know that as soon as more people see this car there will be more buyers. I think it's sad that you are not going on the market, and another great investment for google. Could you please send it out on tour to some of the upscale malls in the country, and for that matter out of the country. The women are at the mall, the daughers are at the mall, the sons are at the mall!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! They see it, they,ll have to have it. It would also be a great way to do a survey as to what people like or dislike about it. I have found that in every state there is a different opinion. Can't wait to see it on the road. Good Luck!!

Richard

11:14am | 10月 25, 2006

I have been doing some more reading on cars lately, and I read about this thing called Brake-by-wire. It is apparently used in race cars because it combines the advantage of a Single-circuit hydraulic system's low weight with a Dual-circuit hydraulic system's isolation of the command circuit.

Perhaps you guys should look into it, as it could potentially reduce the weight of hydralics (by making the tubing shorter and thus requiring less fluid) on the Tesla Roadster. That is assuming that you did not use a brake-by-wire system it already.

Mindy: The story done on NBC's Today show actually showed a woman responding to this car -- reporter Natalie Morales, whose face was perpetually lit by a genuine, almost giddy smile when riding in and driving the Roadster. If you haven't seen that segment yet, Tesla put a link to it on the company home page. Must See TV!

Earl Cox

11:25am | 10月 26, 2006

One way to (loosely) think of a single -vs- 3-phase AC motors is by comparing with 1 cylinder -vs- 3 cylinder Internal Combustion Engines (ICE). With the ICE, each piston that drives the shaft is moving up and down just as the voltage on an AC line goes up and down. A single cylinder ICE simply pushes on the shaft on one crank while a 3 cylinder would push on it on 3 cranks. With the ICE, the cranks would be seperated by 120 degrees while the Phase of the AC lines are also seperated by 120 degrees. Theoretically, is suppose one could use more phases on an AC motor but I'm not sure whether there would be any benefits.

[ I was in grad-school w/Martin (earluy 80's), we were in the same Robotics group. I can still remember him talking about his '66 Mustang. He would lie on the hood, leaned against the windshield..watching meteors at a rest-stop! ]

About promoting cars..

"Race on Sunday, Sell on Monday"

Racing is a great way of promoting cars. Back in '93 Long Beach Grand Prix, they had a demo by an electric race-car. I was at this years LBGP. Toyota is getting into NASCAR in 2007, it's big news. Toyota made a committment to Formula 1 a few yrs ago (they are still title-sponsor to the Long Beach GP). Honda is involved with IRL.

Disc-brakes came about as a development from Racing. There's nothing like "Real World" knowledge to get some help with R&D.

JoeG

11:16am | 11 月 25, 2006

Quote -Joe King: "Tesla Motors is out of touch. Who the Halibut wants to pay $100,000 for an electric car. Just buy the Toyota Prius and alter the battery pack and there you have it. An electric vehicle that can run 400 miles before recharging. It is quite easy to alter the battery pack on the Prius."

Reply: 400 miles before recharging? (not). 350 of those miles will be run on the gas-powered engine. The purpose of the alteration is that you can get your first 50 miles on electricity only and at top speeds of like 40 mph. Not impressive but still a solution for many. This cannot be compared with the Tesla Roadster in any way. The Roadster is, in my opinion, compared to other exotics and highend sport cars. Not a Prius.

JoeG

11:40am | 11 月 25, 2006

Quote -???: "As I learned on Toshiba Web site they disconnected all Li-ion battery technology development and migrated to fuel cell solutions as electricity source for electronics. So I do not believe any battery technology improvement would come as you mentioned. As I see it now (may be it is my mistake but anyway) most prominent battery manyfacturers for electronics who developed Li-ion technology to the level it stands now are migrating into fuel cells.
One interesting approach in fuel cells for laptops I have seen is to use NaBH4 + water to NaBO2 + hydrogen chemical converter in combination with fuel cell. The idea is to get ~10 times energy capacity per unit of mass to generate electricity. Also recharging goes by cartridge replacement with some solid/liquid substance in it. So this approach sidesteps hydrogen delivery/storage problems."

Reply: Tesla guys are usually very good about redirecting comments like this to there blog on the balance of technology http://www.teslamotors.com/blog1/index.php?p=24 and I am suprised people still have this notion that the latest technological breakthrough is going to be the greatest. Everyone is getting exicted about hydrogen as a source of energy. But people must understand that YES, it can be used effectively, but NO it does not have energy stored in it. Not in the same sense of fossil fuels. Fossil fuels have the stored energy of millions of years of plant and animal life compressed into it. Hydrogen carries energy but only the energy put into making it. I am, however, excited about hydrogen, and have been for many years, for a different reason. Fusion!!! The direct conversion of mass to energy is really where you can get energy per gram.

Anyway, I digress. Toshiba's fuel-cell battery has many applications but as Martin and Elon have tried so hard to explain, they chose the best battery technology they could based on ALL of the complicated criteria: Energy Density, Power Density, Weight, Production Volume and of course, COST. Hydrogen is not cheap and is current only mass produced using fossil fuel. Is this Hydrogen (internal) fuel-cell battery rechargeable. Probably not considering you mentioned being replaced as a cartridge rather than refueled. ~10 times the energy storage is impressive but then you have to buy another battery right? Just recharge your Li-ion batteries 50 times and save. How much would this new battery cost compared to equivelant kWh in Lithium? Not mass produced either. How much Power can be extracted in a given amount of time? All these factors weighs heavily on the Tesla company and from thier standpoint, they chose the best solution. Besides, Toshiba may have thier reasons for switching to fuel-cells. They want to sell batteries more often. Laptop energy usage is different than EV's. And they may have incentives from "you know who" to develop hydrogen products. Thank you for taking the time to read my rant. I am calmed down now.

Nischal R

12:57pm | 11 月 28, 2006

I found about Tesla Motors through an article on Slate.com and at first it looked too good to be true. After doing some more research into the company and reading the blog posts I don't think I have been this excited about a new car since...ever! I would encourage all of the people who have posted here to go contact your local senators to encourage support for state tax rebates on Zero Emission Vehicles. Currently several states like mine (CT) don't have any tax rebates for such vehicles (only Federal tax credit) and I think this definitely needs to change. With consistent pressure from their constituents, getting a tax rebate would be like an icing on the cake when driving a Tesla. I'm looking forward to that Sedan. Thanks you Tesla for showing that Green doesn't have to mean boring.

jacksonh

1:11am | 12 月 4, 2006

Thank you so much for your time, attempt and dedication to maintaining this website. I have visited it often.

Richard Marier

11:00pm | 一月 6, 2007

Even if the electric car seems new, it is not... Technology to make it happen is. Today’s internal combustion engines are millions of time better and efficient then the one on the fist Ford model T. If we had invested as much time and money on electric, we would be driving electric cars... I salute Telsa Motor for there development and dedication. This is what the industry needs now. A performance car!
Most people are convinced electric card are not fast or fun of just fantasy prototypes.
Yes the Telsa is expensive, but so was the first Model T then. Not everyone can drives a Porsche... not everyone can drive a Telsa but everyone would! Image is everything... and yours is amazing so far.

I will probably never own a Telsa, but since market is driven by image and not logic (Hummer and other SUV business booming). I imagine this can only change things.

Dennis Buckley

10:06am | 一月 8, 2007

Agent,
Did I missunderstand ? I thought that there was going to be a family 4-door and 2-door
coming out. That lesser price, family car is what I well get in line for.
Respectfully,
Dennis Buckley

I would really like to know who is manufacturing the tesla motor itself. Is this produced by Tesla or someone else?

Kurt Neutgens

9:24pm | 3月 3, 2007

Never Mind, Sorry I didn't read the blog... I was skimming a lot of the website and I guess I got tired.....

So, that brings me to my second question, would you be willing to sell the motor and controller to others?

Thanks!

Ren

1:01am | 3月 9, 2007

I am wondering if the non drive wheels of a car can be made into induction motors. Fill some of the brake disc air journals with copper and mount a coil pack to suspend over the open (uncalipered) area of the disc. This could charge the battery or add to the cars momentum as a low horsepower drive motor. Has anyone tried this?

kevin camilleri

9:42am | 4月 17, 2007

PLS can sombody tell me some advantages and disadvantages of a synchronous machine when compared to an induction motor? i am a student at the electrical and electronic institute in Malta. thankyou

It occurs to me reading this that electric vehicles are probably the greatest impetus for improving electric motor technology in a long time, possibly since they were first invented. If you think about it, marginal improvements in motor efficiency aren't really that valuable in say a blender, a fan, or an industrial application, true, you can save a little in electricity, but a slightly bigger and heavier electric motor probably isn't going to significantly affect the product or application. In a car, however, motor efficiency translates directly into fuel economy, range, performance to some degree, and/or the size and cost of the battery pack. For example, an electric motor that is 10% more efficient but costs $1000 more could use a 10% smaller battery pack (ignoring the energy required for accessories), saving $2000 and 90lbs on a $20K, 900lb battery pack, and requiring less power density and/or discharge rate, resulting in a less expensive, better-performing vehicle.

It implies to me that we will see accelerated improvement in electric motor technology in coming years as companies like Tesla and others build and improve electric vehicles, and that electric motors are another area in addition to battery technology in which electric vehicle technology will improve substantially going forward.

RDE;
if you can't handle white on black, click on the page and do a CTRL-A. The "highlighting" will invert the contast scheme.

Mark

7:07pm | 7月 28, 2009

I have a dead motorcycle, a 1992 Yamaha Seca II, I have watched U tube video's with great interest, and considered the possibility of converting my bike to electric.
I agree that an A/C motor would be my best bet, However the thought occurs to me, that It could be run as a hybrid, Using a 50 cc fourstroke portable generator, at 28 lbs, (Honda or Yamaha)( $859 new with warranty @ 1000 ) plus the weight of the A/C motor, It would be light and nimble, should hold up well for some time, and still be very fuel effecient.
Add the capacity of the existing fuel tank (4.3 gallons) to the run time on 3/4 Gallon tank that comes with the generator
posting 4 hours of continuous run time, It should have considerable range.

What do you think the best means of controlling the throttle would be, and would I have to consider feedback from coasting

R Monroe

2:32am | 9月 23, 2009

I always wondered with todays abilities why couldn't you incorporate generators into the wheels that help recharge 2 or 3 extra batteries that a computer could add too and remove from the battery block in otherwords charge them change to 3 other charge them then pulll 3 more charge them using 200 amp generators incorportated into the wheels to save weight. This idea is not for perpetual motion just for longer distance all done with a computer system . If you can use the power of the brakes to produce electicity why not the power of the rolling wheels that move the car? if this is an idea that you can use please email me if not please explain why not by email

EVMotorMan

4:03pm | 3月 15, 2012

You will be aware of the phrase: "There is no such thing as free energy"

You are right Mr Monroe - all motors can become generators and this reversal is how they achieve regenerative braking power. Pedal off, motor adopts generator mode - motor turns into generator and loads batteries.

The process though is not FREE as it absorbs prorata "energy" in the form of resistance as magnets within the generator attract and repel one another - and it is this resistance that enhances the braking.

Simplified, supposing you build am EV with two motors driving the back wheels and two generators collecting kinetic energy through the front wheels. Your batteries send 60kW of power to turn your back wheels - and you obtain 60mph.

Any front wheel generators (or maybe generators built-in to the same motor wheels) - at that RPM would be attempting to generate 60kW of power - and therefore the resistance/drag is 60kW.

Result - the car would not go anywhere.

Proof of concept is to try turning an electric in-hub motor/generator by hand - can't be done. It takes "energy" to overcome the resistance of the induction process inside the motor. Obtaining that 'energy' from the movement of the vehicle on the road (kinetic energy) - WILL turn the generator and charge the batteries. But if you need the same energy to obtain the movement - one cancels out the other.

Other ideas for harnessing power from the kinetic energy produced by moving vehicles involve wind turbines turned by air moving around fast moving traffic and pressure studs in the road - but there's a long way to go!

The only FREE energy in the world today is from the HO-JO Howard Johnson Magnetic Motor - the biggest scam on the planet right now!